1. Field of the Invention
The present invention generally relates to the representation of data in machine readable form and more particularly to a system for the encryption of data into a two-dimensional graphic image that can be automatically machine read to obtain the encoded data in both open and closed systems.
2. Description of the Prior Art
In todays high technology world more and more operations are being automatically performed by machines and systems. This ever-increasing drive for automation has resulted in a demand for new techniques for encoding data into machine readable form for automatic entry into the various systems and machinery. The data entry may be for such uses as data transmission, operating various machine functions or the identification of persons or items. The various media that carry the data for automatic entry include punch cards, magnetic tapes and discs and magnetic stripes on cards such as credit cards and badges. The systems utilizing the above carriers are in "closed" systems, i.e. the read function is performed within an apparatus or housing and the reading element is in contact or in near-contact with the carrier means during the reading operation.
One method for representing data in a machine readable form is to encode the data into a pattern of indicia having parts of different light reflectivity, for example, bar code symbols. A bar code symbol is a pattern comprised of a series of bars of various widths and spaced apart from one another by spaces of various widths, the bars and spaces having different light reflective properties. The bar code symbol is optically scanned and the resulting electrical signals are decoded into data representative of the symbol for further processing. Bar code reading systems are known as "open" systems in that the carrier while being read is not sealed, but is read from a distance and without being in physical contact with the scanner.
The conventional bar code described above is "one-dimensional" in that the information encoded therein is represented by the width of the bars and spaces, which extend in a single dimension. Similarly data encoded onto other media such as credit card magnetic stripes is composed of one or more "one-dimensional" tracks of encoded data.
The use of bar code symbols and magnetically encoded data has found wide acceptance in almost every type of industry. However, the one dimensional nature of the encoded data limits the amount of information that can be encoded and hence use has been generally restricted to simple digital representations.
Thus, there is a need for a system to encode data in machine readable form that allows for an increase in the amount of data encoded into a given space that can be quickly and easily decoded for further processing.